Many times I prefer to use fullsized images instead of thumbnails in my articles. Is there a way to make the vB attachment tag show the fullsized image instead of the thumbnail? Kind of Attachment fullsize BBcode?

Too problematic for a number of reasons... Many would get on fine with it, but more wouldnt. I think the coolest thing would be a hover popup that would make it full or medium size. In fact, IMO... vB needs to tumb and mid size the pics. Then you could specify the size for medium pics and insert those. If the pic is larger.. clicking it would bring the full size up in another window.